tbaeder added inline comments.
================ Comment at: clang/lib/AST/Interp/Opcodes.td:502 + let Types = [AluTypeClass]; + let Args = [ArgFltSemantics]; + let HasGroup = 1; ---------------- jcranmer-intel wrote: > tbaeder wrote: > > sepavloff wrote: > > > tbaeder wrote: > > > > jcranmer-intel wrote: > > > > > Integer-to-floating point conversion is dependent on rounding > > > > > mode--consider `(float)UINT_MAX`. > > > > This test succeeds here, whether I use `-frounding-math` or not: > > > > > > > > ``` > > > > constexpr float f = (float)4294967295; > > > > static_assert(f == (float)4.2949673E+9); > > > > ``` > > > > How can I test this behavior? > > > You can use `#pragma STDC FENV_ROUND`. See > > > `clang/test/AST/const-fpfeatures.c` as an example. > > Why does it work here to compare both `f` and `f2` to the same value? > > https://godbolt.org/z/zdsf1sK7r > `FENV_ROUND` is a new feature of C2x, so it doesn't look like it's properly > handled in gcc or clang yet. (It's for sure not handled in clang--the code to > convert a floating-point literal into an `APFloat` hardcodes default rounding > mode in its call.) > > Dynamic rounding mode shows you the difference: > https://godbolt.org/z/856xM8KTh So I can't test this at all because it first needs work in clang to do the float->APFloat conversion correctly? CHANGES SINCE LAST ACTION https://reviews.llvm.org/D134859/new/ https://reviews.llvm.org/D134859 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
